Hybridization in Chemistry:
The difficulties in correlating the ground-state electronic configuration of elements like C, Be, B, P, S, etc and the maximum covalency exhibited by them in their compounds can be overcome by the concept of hybridization of electron orbitals which also explains the directional character of the hybrid bonds in space and also the shapes and structures of covalently bonded molecules and ions.
Hybridization is the mixing up of atomic orbitals of similar energies and redistribution of electrons in different orbitals in the valency-shell of an atom, creating a new set of identical orbitals. It involves two steps:
i. Excitation of electrons
ii. Re-orientation
Types of Hybridization:
There are mainly three types of Hybridization:
- sp3
- sp2
- sp
sp3 (Tetrahedral Hybridization):
This type of Hybridization involves mixing of one s and three p orbitals to give four equivalent sp3 hybrid orbitals. These orbitals are directed toward the four corners of a regular tetrahedron having bond angles of 109°28′.
sp2 (Trigonal Hybridization):
This type of Hybridization involves mixing of one s and two p(px, py) orbitals to give three equivalent sp2 hybrid orbitals. The three sp2 hybrid orbitals are directed towards the three corners of an equilateral triangle with an angle of 120°. An sp2 hybrid carbon atom has three sp2 hybrid orbitals and one pure p-orbital. This type of Hybridization takes place in the formation of alkenes, benzene, boron halides, etc.
sp (Diagonal Hybridization):
This type of Hybridization involves the intermixing of one s and one p orbital to give two equivalent hybrid orbitals knowns as sp hybrid orbitals. The two sp hybrid orbitals are directed diagonally in a straight line with an angle of 180° (collinear orbitals).